What could cause bald spots in facial hair?

Alopecia Areata: Alopecia areata is the most common cause of round bald spots in facial hair. The disorder is oftentimes self limited. In some cases, a series of topical treatments or local injections can be helpful.

Fungus: One can contract a skin fungal infection that will cause loss of skin color and occasionally hair. It is usually circular and grows slowly. It can be treated with oral medicines and lotions.